Well, it should not sell for $1200 to begin with, not in the world where Tamron 28-75 f/2.8 was introduced at $400. Introduced 6 years ago (and computer-aided lens design and aspheric lens molding technologies progressed a lot since then) a lens full stop faster was selling three times cheaper despite the limitations of long registration distance (don't feed me crap about long reg. distance being an advantage -- I am a professional optical engineer) while being almost as light (500 grams vs 430 g).

Actually, the Tamron 28-75mm XR Di was introduced back in 2005 when I purchased my first one with a D70; I still own it and a second I bought second-hand to use with my pair of D7000s in medical video.

Yes, you are right. Then there is even more weight to my point: the lens developed 9 (!!!) years ago, aspheric elements were WAY more expensive then than they are now.A lovely lens, I had one in Canon mount, and bought one now for joint use on my Nikon/Sony setup (Nikon mount obviously).

That Tamron has been made in a variety of mounts for more than 10 years now - Canon, Nikon, Sony Alpha, and probably others.

Well, Tamron didn't know how many copies they would sell when they set a price point at $400.

Sony FE lenses fit only Sony E mounts - and they were engineered in 2013, with 2013 manufacturing costs...

... which are much cheaper than those in 2005.

Just inflation would make that Tamron 40% more expensive if designed and manufactured today.

That it would. However, this price increase would be more than offset by reduction of manufacturing costs of aspheric elements -- which are pennies compared to what they were 10 years ago. Lens prices are indirectly (to say the least) related to the manufacturing cost.

Sony FE lenses are, relatively speaking, almost custom lenses - so few cameras can use them. It knows its market. And all longer than 35mm have OSS

Really? My FE 55/1.8 has OSS? That's news to me.

All NEX and other Sony APS-C cameras can use them of course.

I found something in an obscure Sony Sales website which was a comment made by somebody, about 2 weeks ago. The comment was that the FE 55 has OSS and I was the one who posted it. But I have not seen any confirmation of that yet, so I would not say that with any degree of certainty.

That's one reason why a 55mm OSS Sony lens costs $800 and and a Nikon non-VR 50mm costs under $200.

I'm not very familiar with Sony line-up, so I'm not aware of any 55/1.8 lens with OSS for $800. There is an APS-C format lens 50/1.8 with OSS for $300 and FE 55/1.8 without OSS for $1000. Which one did you mean?

It is FE 55 mm f2.8, not 1.8.

Nikon assumes anyone who wants a fast 50mm doesn't need VR.

That Nikon is an interesting lens: the only one in 50/1.8 class having an aspheric element. It performs very well for the class, and I guess Nikon didn't make it to perform even better (with more aspherics, e.g. Sony FE 55 has three of them) in order not to kill the sales of more expensive lenses.

Sony sells to amateurs willing to pay $600 more to get OSS in a 55mm prime.

Again, I'm confused here. Then again, in my opinion neither lens should have OSS, it belongs to the body, Olympus style.

School's still out on the FE55 having OSS.

Olympus don't use in-lens stabilization. Theirs is called IBIS and it's internal to the body.

That $400 Tamron has no OSS. I can't imagine the majority of those complaining about Sony's roadmap or pricing accepting a 28-75mm at $400 if it didn't have OSS.

At $400 with f/2.8? In a heartbeat. It is quite common (e.g. Canon-Nikon) to price f/4 normal zooms with OSS at 50-70% of f/2.8 lens without one.

As an optical engineer, you recognize the difficulty of simply putting Nikon/Canon formulated lenses in a Sony PDAF optical system.

Depends what lens we are talking about, and who puts it in. If Sony does it, it is not very difficult: Sony has the phase sensor's data. Yes, most SLR-developed lenses are neither easy to transplant (in autofocus mode) nor should be transplanted in the first place. However, at $400-500 this Tamron costs today (new!), many would buy it even as a manual focus lens (all T needs to do is put in a proper (light) extension/mount, mechanical aperture, rework the helicoid and ditch the AF gears/motor). Heck, I prefer it even with a heavy Fotodiox adapter (with aperture control).

Mirrorless designs on the other hand are very easy to design/transplant. I can design such a lens (well, its optical formula anyway) -- not from scratch of course, but derive it from existing designs.

Sigma 30/2.8 covers>80% of Full frame already. Same trick: enlarge every element by 20% and get 36/2.8 -- and Sigma already has autofocus protocols for NEX! And, unlike PDAF, CDAF never misses (well almost never, sometimes i locks on the wrong object such as background).